Submerged motor-driven pump and fluid pressure system for variable pitch propellers



H. M. GEYER ET AL OR-DR Nov. 23, I954 SUBMERGED MOT IVEN PUMP AND FLUID PRESSURE SYSTEM FOR VARIABLE PITCH PROPELLERS 5 Sheets-Sheet 1 Filed May 26, 1951 INVENTORS Hawara M Gaye!" Haber! C. Twas? M ATTORISZYS NOV. 23, 1954 GEYER E 2,695,070

SUBMERGED MOTOR-DRIVEN PUMP AND FLUID PRESSURE SYSTEM FOR VARIABLE PITCH PROPELLERS Filed May 26, 1951 3 Sheets-Sheet 2 M AT TORNE Y5 Jay 3.

1954 H. M. GEYER ETAL SUBMERGED MOTOR-DRIVEN PUMP AND FLUID PRESSURE SYSTEM FOR VARIABLE PITCH PROPELLERS Filed May as, 1951 3 Sheets-Sheet 3 N v w-mms United States Patent Ofice 2,695,070 Patented Nov. 23, 1954 SUBMERGED MOTOR-DRIV EN PUMP AND FLUID PRESiURE SYSTEM FOR VARIABLE PITCH PRO- PELL RS Howard M. Geyer and Robert C. Treseder, Dayton, Ohio, assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application May 26, 1951, Serial No. 228,458 9 Claims. (Cl. 170160.21)

This invention relates to fluid pressure control systems in which a selectively operable electric motor-driven pump with its motors are submerged, inundated, or immersed in the fluid medium of the fluid pressure system.

A principal object of this invention is to provide a pump and driving means therefor that may be operated for supplementing a system operated pressure developing means under conditions where the normal flow is insuificient, and that may be operated or submitting or replacing a system operated pressure developing means at any time.

A further object of the invention is to provide an additional pressure developing means adapted for use in a rotatable structure having a fluid pressure system including a reservoir, control apparatus and a self operated pressure developing means, which additional pressure developing means may be operated while the structure is rotating to supplement the self operated means, and may be operated while the structure is not rotating to substitute or replace the self operated means.

To accomplish the objects, an electric motor is enclosed in a housing that is substantially fluid tight except flow from the controlfor openings through which fluid apparatus may flow, pass through the motor housing around the rotor and windings and then exit to a scroll or battle. The motor drives a gear pump and has a fluid connection to the system and from the interior of the motor housing, the pump and motor as a unit being mounted in the rotatable reservoir so as to be immersed in the fluid medium thereof. The pump is always primed and the motor windings and bearings are cooled by the return flow from the system. Brush and slip-rings provide means for selected operation of the motor driven pump whether the structure be at rest or rotating.

Fig. 1 is a schematic showing laid out as a longitudinal section of a rotatable structure, in this instance an hydraulically controlled propeller, in which the instant invention is embodied.

Fig. 2 is a front elevational view of a motor-driven pump, substantially as indicated by the arrow 2 of Fig. 4.

Fig. 3 is a rear elevational view.

Fig. 4 is an axial sectional view of the motor-driven pump substantially as indicated by the line and arrows 4-4 of Fig. 3.

Fig. 5 is a fragmentary showing in section substantially as indicated by the line and arrow 5-5 of Figs. 2 and 3.

Fig. 6 is a transverse sectional view through the terminal board substantially as indicated by the line and arrow 6-6 of Fig. 2, and showing the means and method of conveying electric current to the motor.

Fig. 7 is a transverse sectional view through the motor housing substantially as indicated by the line and arrow 77 of Fig. 4.

Figs. 8, 9 and 10 are fragmentary views illustrating the relation of a motor driven pump and its rotatable mounting in selected positions as it revolves about a center 0.

With reference to the drawings, and first with respect to Fig. 1, a rotatable assembly or unit is shown in which a fluid pressure system is embodied that is primarily energized by a pump responding to rotation of the assembly for supplying a pressure line leading to control valves for controlling the application of fluid pressure to either side of a reversible fluid pressure motor upon the communication of intelligence to the control valve by either automatic or manually controlled means. In this instance the rotatable unit comprises an aircraft propeller 10 driven by a shaft 12 having bearing 14 in a gear casing or engine nosing 16 as is the usual practice. The propeller unit 10 comprises a hub 18 with pitch shiftable blades 20 having bearings 22 in sockets 24 radiating from the hub 18. Each blade is shifted in pitch by a rotatable cylinder 26 pinned thereto and to a blade gear 28 by a dowel or like device 30.

Within the cylinder 26 there is a piston 32 having a helically splined engagement at 34 with the cylinder 26, and a helically spiined engagement at 36 with a spindle 38 radiating from the hub 18. The piston 32 divides the cylinder 26 into a decrease pitch chamber 40 and an increase pitch chamber 42. It is understood of course, that each fluid pressure servomotor comprises a cylinder 26 with a piston 32, and that each blade 20 is provided with such servomotor and that all are interrelated by a master gear 44 meshing with all blade gears 28 so as to coordinate and correlate or equalize the blade movements in a pitch shifting sense. All of the pitch decrease chambers 40 are connected by passage 46 and joined to a common conduit 43 that opens at one end to a decrease pitch port 50 of a governor valve 52. All of the increase pitch chambers 42 are connected together by passages 54 and joined to a common conduit 56 that opens at one end to an increase pitch port 58 of the governor valve 52. A pressure supply port 60 opens to the governor valve 52 between the ports 50 and 58 and leads by a conduit 62 to a chamber 64 of a pressure control valve 66 which chamher is also connected by passage 68 to a system pump 70 providing a pinion 72 mounted for rotation by gear 7 4 carried by an adapter assembly 76.

The governor valve 52 provides a bore 78 within which is movable a valve plunger 80 that has lands 82 and 84 cooperable with the ports 50 and 58 respectively for controlling the flow of fluid pressure from the source port 60 to either side of the servo motor piston 32. A lever 86 is articulated to the plunger 30 and is urged into engagement with a movable fulcrum 88 by a spring 90, the governor valve 52 being so mounted that the bore 78 is radially disposed with respect to the axis of rotation O and is responsive to centrifugal force in opposition to the force of spring 90 to vary the radial position of valve plunger 80 in the bore '78, an equilibrium position being reached when the lands 32 and 84 cover the ports 50 and 58. The point at which equilibrium will be reached is effected by a control ring 92 operable to move the fulcrum 88 to difierent positions along the length of the lever 36. Screw shafts 94 threading into the control ring 92 have journals in the gear flange 74 and terminate with pinions 96 engageable with a circular rack 98 whose oscillation is controlled by a manual lever 100.

The pressure regulator valve 66 includes a plunger 102 providing a pressure piston 104 movable in a chamber 106 communicating by passage 108 with the conduit 56 connected with the increase pitch chambers 42 of the servo motors and with the increase pitch port 58 of the governo'r valve. The piston 104 is therefore exposed on one side to the pressure existing in chamber 106 and on the other side to the pressure existing in the chamber 64 and is so constituted it operates in the metering sense to Variably close an exhaust port 110 for relief of excessive pressure in the pump line 62. This valve is responsive to centrifugal force and is assisted in radial outward movement by means of a spring 112 so that the potential of pressure maintained in the pump line 62 will be relatively low upon onspeed operation, but will immediately be stepped up according to pressure demand when the governor valve directs fluid pressure to either control port.

The foregoing defines a rotatable structure embodying a self energized fluid pressure system with control means adapted to direct fluid pressure to either side of the servomotor to control blade shift movement as called for by either the manual means in setting the fulcrum 88 to call for some specific speed setting, or as called for by shift of the governor valve 52 when there are variations in speed operation from that called for by setting of the manual means 100. The hydraulic structure operating to control the movement of the motor is embodied in what is called a regulator consisting of an annular plate 114 mounted on and rotatable with the hub 18 and united with a cover 116 to provide a reservoir 118 within which all of the control mechanism is enclosed, it for the most part being mounted directly on regulator plate 114. The inner bounds of the regulaor rather the reservoir 118, is closed off by the through the use of proper seals, though not so shown. The adapter assembly is restrained against rotation with the regulator by means of lug and abutment means 120 provided by the adapter assembly 76 and gear casing 16. By that means, when the propeller rotates, which is accomplished by drive of the shaft 12, the regulator rotates with respect to the adapter assembly such that the pump gear 72 rolls around the gear '74, and so that a shoe 122 of the fulcrum carriage 88 slides in a groove of control ring 92. The cover 116 of the regulator also rotates with respect to the adapter assembly and with respect to the gear casing 16.

That construction provides for automatic development of a fluid pressure potential whenever the propeller is rotating, but does not provide any source of pressure while the propeller is not rotating. In some constructions, and particularly in that for the control of aircraft propellers, there is a need for a pressure potential at times when the propeller is not rotating, and sometimes it is desirable to supplement the flow of fluid in the system while the propeller is rotating. That need is particularly desirable when'blade pitch changes of considerable magnitude are desired or are called for. Some of those needs might arise at the conclusion of feathering, or, during a change into or out of negative pitch, or to changes of great magnitude within the governing range of the propeller operation. A motor driven pump 138 is therefore provided so that it may be operated at any time whether the propeller is rotating or not. In this em bodiment as shown in Fig. l a pump 132 is driven by a motor 134 and shaft 136 energized by the leads 138, 148 and 142 forming a cable 144-.

The motor is enclosed in a housing 145 from which a port 146 opens to the pump 132 whose delivery passage 148 connects with a check valve 158 opening into the pressure source line 62. The valve 150 is so constituted that fluid under pressure may flow from passage 148 into conduit 62, butsothat fluid in the conduit 62 may not flow into the passage 148. A pump control valve 152 controls the connection between the pump 132 and the pressure line 62. The valve unit 152 provides a bore 156 which opens by port 158 into the low pressure side of the relief valve 150 and also opens by port 168 into into thepressure line 148 communicating with the pump 132. Slidable within bore 156 there is a plunger 162 urged radially inward by a spring 164 and having a piston face 166 always exposed to pressure in conduit 62 through the port 158. When the pressure in the conduit 62 is of satisfactory potential (500 p. s. i. or more) the valve plunger 162 will be forced radially outward so as to connect port 168 with an exhaust passage 168 that communicates with a sump or well 170 which has openings 1'72 communicating with the interior of the motor housing 145.

The motor housing 145 also has an' opening 174 into a scroll or baflie 176 surrounding the motor housing and exhausting at 178 into the reservoir 118. The sump 170 also collects drain or return flow fluid medium from the blade servomotors by way of the governor valve 52. Each end of the bore 78 is open by ports 180 or 182 to a passage 184 connecting with the sump 170 as shown in Fig. 1. Drain of fluid from either chamber 46 or 42 of the servomotor follows passage 46, or 54, conduit 48 or 56, through port 50 or 58 and 180 or 182 then through 184 to 170, which also collects return fluid from the pump control valve 152 if the output of pump 132 is not connected with the system trunk line 62. By returning all drain from the servomotors and the control valves to the sump 170 there is collected a mass of cool fluid medium that flows through the openings 172 of the motor housing, between the motor parts and out the opening 174 to the closed end of the scroll from where it empties into the reservoir 118 at 178. The pump 132 is therefor always primed because its intake 146 is from the interior of the motor housing, and the windings and bearings of the motor driving the pump are adequately cooled by the return of the fluid from the blade servomotors.

The detailed construction of the motor driven pump is illustrated by Figs. 2 to 7 inclusive of the drawings, to which reference is now made. Motor end frame 190 provides a socket 192 for the journal of the armature shaft 136 that supports armature laminations 196 fitted with conductors 198 axially disposed within the stator laminations' 200 carrying field windings 202. The other end of tor, adapter assembly 76 that lead the armature shaft 136 has bearing in a bushing 204 secured in one end of the motor housing 145. The motor housing is of cup form whose rim 206 surrounds a flange 208 of the end frame 196, a seal 210 being disposed between them. The stator of the motor is thus enclosed within a sealed chamber provided by the end frame 190 and the housing 145.

A space plate 212, and a mounting plate 214 are clamped against the flat face of the end frame 190 where they are located by pins 216, and the space plate 212 is appropriately apertured to receive a pair of gears 218, 228 constituting the pump 132.

Along a tangent to the intersecting pitch lines of the gears a channel 222 is formed in the space plate 212 to connect pump intake port 146 with a pump outlet port 224. As shown in Fig. 5 the pump intake port 146 is formed by aligned holes in the end member 198 and the space plate 214 and is disposed in one end of the channel 222. The pump outlet port 224 is formed by a bore through the plate 214 communicating with the other end of channel 222. As shown in Figs. 3 and 4 the passages 172 connecting the sump 176 with the interior of the motor housing are formed by a plurality of drill ways through the end plate 190, the space plate 212 and the mounting plate 214. As shown in Fig. 4 the pump gear 220 has axial extensions 226 and 228 having journal hearings in the mounting plate 214 and end member 190 respectively, and the pump gear 218 has a similar bearing and support. The axial extension 228 of the pump gear 220 protrudes from the mounting plate 194"; to be concentric with the armature bearing 192 and has driven engagement with the motor shaft 136.

Mounted on the outside of the motor housing 145 the scroll 176 covers the opening 174 and extends about three-quarters of the way around the perimeter of the housing to terminate with the open end 178. The other end of the scroll that is the end near the opening 174, is closed by a head member 230 so that fluid exit from the opening 174 must follow the extent and contour of the scroll 176 before it can exit into the reservoir at 178. The cable 144 by which electrical energy is put into the motor, lies within the confines of the scroll 176 substantially as shown in Figs. 2 and 7 and exposes the leads 138, 140 and 142 for passage through the opening 174 to the motor windings 282, and supports them at the other end on a terminal board 232 which is carried by brackets 234 provided by the mounting plate 214. The terminal board and terminal construction are shown in detail in Fig. 6 where a nonconducting body 236 is provided With terminals 238, 24 and 242 to which the leads 138, 140 and 142 are electrically connected. The non-conducting plate 244 covers the terminal junctures and is supported by the brackets 234 by means of rivets or the like 246.

The motor-driven pump 130 as so constituted forms a sealed motor and pump unit adapted for mounting in the regulator of the propeller which is accomplished by threading bolts or other screw devices through apertured lugs or ears 248 of the mounting plate 214 and threading them into the body of the regulator plate 114. Figs. 4'

and 5 show the unit mounted in that fashion where it will be observed that the regulator plate 114 provides a large recess or well for the sump over which the motor driven pump is mounted. A circumscribing groove receives a seal ring 250 which is under compression when the motor unit is mounted on the regulator plate, thus preventing flow from the sump 170 except through the passage 172, through the motor housing, through the aperture 174 and around the scroll 176 to exit 178. The drain back, or return flow of fluid from the system, enters the well 170 by means of a port 252 as a terminus of the drain passages 168 or 184. When the motor driven pump is so mounted the electric leads of the cable 144 are joined to brushes 254, 256 and 258 insulatingly supported by the rotatable regulator cover 116. These brushes engageelectric slip rings 260, 262 and 264 insulatingly supported by a plate 266 stationary with respect to the gear casing 16. Conductors 268, 270' and 272 connect the slip rings 260, 262, 264 with terminals of a control switch 274 adapted to control the application of electrical energy from a power source over the line cable 276; the electrical potential being in the order of 200 volts,.three phase, switch 400 C. P. S. The switch 274 may be a gang operated by a solenoid 278 through closure of a manual switch 280 leading to a current source of suitable characteristics.

Reference is now made to Figs. 8, 9 and 10, for features of mounting and operation of the motor-driven pump, the several views being disposed to show the relation of the parts as the pump, mounted on an annular plate 114, revolves about the center on the diameter D-OD. When the pump unit is mounted on the regulator plate 114, it will be noticed that the channel 222 extends substantially radial of the plate 114 as it rotates about the center 0, so that, as shown in Fig. 5, the channel 222 connects by port 146 with the interior of the motor housing at one end, and at the other end connects by port 224 with a port 282 in a pad 284 embedded in the plate 114 and opening into passage 148 through port 286. In Figs. 8, 9 and the output passage 148 and the drain-back passage 184 by which the sump 170 is supplied with fluid at all times, are shown in dashed lines, since they are embedded in the body of the plate 114.

When the propeller is conditioned for operation, the regulator is filled about half full with the fluid medium by which the control is to be effected. If Figs. 8 to 10 can be regarded as a complete regulator, then the fluid medium would stand substantially at the level DO-D, and under static conditions, the pump and motor at any the fluid medium. If it be assumed that a condition of great depletion of fluid medium has taken place, and the regulator is not rotating, there is still an ample supply of fluid in the motor housing to prime it if its use is demanded while the propeller is at rest. The minimum level of fluid in the motor housing in each case of Figs. 8, 9 and 10 is indicated by the lines marked by the letters S-L. If the propeller is rotating, then the fluid in the regulator will lay along the outer periphery of the reservoir somewhat as indicated by the curved line indicated by the letters RS in Figs. 8, 9 and 10. The outlet from the scroll 176 is immersed to such extent that fluid is which in addition to the always available for the pump,

fact that with each unit of fluid taken up by the pump and forced into the system through the passage 148, there is an equal volume leaving the system by either the pump control valve 152, or the governor valve 52, the drainback from which is led by the passages 168 and 184 to the sump 170. The return fluid reaching the sump 170 must flow through the motor housing before it can reach the pump 132 to return to the system, or return to the reservoir, and therefore aids in cooling the bearings and windings of the motor.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows::

1. In a fluid pressure control system for a rotatable aircraft propeller having pitch shiftable blades, the combination comprising, a reservoir containing a fluid pressure medium, a propeller having a plurality of blades mounted for rotation about their longitudinal axes to alter the pitch thereof, double acting fluid servo-motors operatively connected to said blades for changing the pitch thereof, means within the reservoir and operable upon rotation of the propeller for creating from said fluid pressure medium a source of fluid under pressure, means rotatable with the propeller for directing the application of said fluid under pressure to the servo-motors for effecting a predetermined control of said blades, an electric motor-driven pump mounted in the reservoir and immersed in the fluid medium thereof, a housing enclosing the electric motor and opening to the reservoir, a sump chamber collecting the exhausted fluid medium from the fluid servo-motors, an outlet from the sump into the motor housing whereby the return flow of fluid medium from the fluid servo motors to the reservoir must pass through the motor housing, an intake for the pump connected with the motor housing, source pressure controlled means for connecting the pump outlet with the source of fluid under pressure, and means controlling the operation of said electric motor-driven pump.

2. In a fluid pressure system for the control of blade pitch in an aircraft propeller by directed application of fluid under pressure to and from blade actuating servomotors, the combination comprising, a rotatable propeller having a plurality of blades mounted for rotation about their longitudinal axes to different pitch positions, fluid pressure operated servo-motors operatively connected to said blades for adjusting the pitch position thereof, a reservoir rotatable with the propeller and containing a quantity of fluid medium, means within the reservoir for continuously placing a portion of said fluid medium under pressure during rotation of the propeller to be directed to and returned from the blade actuating servo-motors, an electric motor and pump driven thereby mounted in the reservoir and immersed in the fluid medium thereof, a housing enclosing the electric motor and having an outlet to the inlet of said pump, means conducting the return flow from the blade actuating servo-motors to the interior of said motor housing, a circuitous passage leading from the interior of the motor housing and opening to the said reservoir whereby return flow from the blade actuating servo-motors to the reservoir operates to cool the electric motor, means connecting the outlet of said pump to the fluid pressure system, and means for controlling the operation of said electric motor and pump Whether the propeller be rotating or not rotating.

3. A fluid pressure system for the control of blade an aircraft propeller operable in constant speed, featherlng and negative pitch regime by application of fluid under pressure to and return flow from double acting servo-motors, comprising in combination, a rotatable propeller having a plurality of blades mounted for rotation about their longitudinal axes to different pitch positions, double acting fluid pressure operated servo-motors operatively connected to said blades for adjusting the pitch position thereof, a reservoir rotatable with the propeller and containing a quantity of fluid medium to be applied to the servo-motors, means within the reservoir and operable during propeller rotation for placing a medium under pressure, a valve unit for applying the fluid medium under pressure to either side of the double acting servo-motor and for guiding the return flow of fluid medium from the said servomotors, manual means operable upon the valve unit for selecting the direction of application of fluid medium to and return flow from said servo-motors, an electric motor and pump selectively operable for supplementing the propeller operated means for placing a portion of the fluid medium under pressure, means mounting the electric motor in the reservoir so as to be immersed in the fluid medium thereof, passage means for conducting the return flow of fluid medium from the servo-motors to the interior of the electric motor, means connecting the inlet of said pump with the interior of the motor and the outlet thereof with the system, and manually operable means for controlling the actuation of said electric motor and pump.

4. The combination set forth in claim 3, wherein a pressure actuated valve controls the connection of said pump output with said system and responds to the fluid medium under pressure produced by said means within the reservoir for disconnecting the output of the motor driven pump from the system.

5. The combination set forth in claim 3 wherein the manual means operable upon the valve unit may effect propeller operation in either the feathering or negative pitch regime, and a pressure propeller is used for connecting the output of the motor driven pump with the system near the end of propeller operation in the feathering regime, and means including said pressure responsive valve for substituting the output of the motor driven pump for the fluid under pressure by propeller rotation when feathering, unfeathering and negative pitch operation of the propeller is called for during non-rotation of the propeller.

6. In a fluid pressure system having a rotatable reservoir partially filled with a fluid medium, an electric motor driven pump adapted to be immersed in the fluid medium of the reservoir and operable to deliver the fluid medium under pressure to the system, a housing enclosing said motor and having an opening to the reservoir, means connecting the return flow from the system to the motor housing for cooling of the motor, passage means connecting the pump inlet with the interior of the motor housing, and means mounting the motor in the rotatable reservoir so that the pump is always primed by the fluid medium Within the motor housing.

7. The combination set forth in claim 6, wherein a circular scroll extends from the opening of the motor housing more than half way around the motor housing, the

medium placed mesa-om end. of said. scrolli adjacent the motor housing opening being closed and theother end of saidscroll beingzopen; said scroll being so located that. apredetermined level of fluid medium for primingthe pump is maintained in said motor housing irrespective of the angular position of. the rotatable reservoir;

8.. In a fluidv pressure system, a rotatable structure constituting a reservoir which is partially filled? withfiuid medium, said rotatable. structure including. a plate. member and a cover member, means constituting a sump chamber. in said plate member, an electric motor: having a' housing attached to said plate member, said housing having an opening communicating with said sump chamber and through which exhaust of fluid from the sump chamber must fiow,.a pump driven by said electric motor, said pump having an intake communicating with the interior of said' motor. housing. and an outlet connected with the system, passage means connecting the return flow from the system to said' sump chamber, and means constituting an outlet passage from said motor housing. communicating with said reservoir, said outlet passage being so located that irrespective of. the: angular position. of said rotatable structure, a predetermined level of fluid medium for priming the pump ismaintainedin. the motor housing.

9; In a fluid pressure system, the. combination including, a first source of fluidpressure, a systemsupply passage, a second source of. fluid pressure comprising an electric motor driven pump,.a sumpv chamber from which W from said sump chamber to said pump: through first passage means directing fiuig sat motor: whereby cooling: of said motor is effected, and second" passage means connecting the output of said pump to said: system supply passage. including a check valve; one" side of which is exposed to the pressure of said system passage andthe'other side of which is exposed to the pressure output of saidpump', and a pressure relief valve: havingana inlet port connected with the output of said pump,.. an. outlet port connected to said sump' chamber, and a plunger. having at surface exposed. to the pressure in said: system passage whereby communication betweensaid second passage-means and said system supply passage istblocked and the output of saidpump is diverted to said. sump chamber when the pressure in said system supply passage is above a predetermined potential.

References Cited in the file of this patent UNITED STATES' PATENTS Number Name Date 1,347,732 Cooper July 27, 1920 2,229,058 Dicks Jan. 21, 1941 2,291,953 Dicks Aug. 4, 1942 2,356,243 Huber Aug. 22, 1944 2,356,306 Davis Aug. 22, 1944 2,556,435 Moehrl et a1. June 12', 1951 2,611,440 Haworth et al Sept. 23, 1952 

